Sighting means for aeroplanes.



L. U. WETHERALL.

SIGHTING MEANS FOR AEROPLANESV APPLICATION FILED IMYZ. I911.

Patented y 21, 1911 2 SHEETS-SHEET I.

WITN ESSES ATTQRNEY L. U-.' WETHERALL. SIGHTING MEANS FOR AEROELANES.

APPLICATION flLED MAY 2. I917- Patented y 21,1918.

2 SHEETS-SHEET 2 INVENTOR WITNESSES ATTORNEY M i ll SIGHTING MEANS FOR AEROPLANJES.

memes.

Specification of Letters Patent.

Patented May 21, 191.

Application filed Mayit, 1917. Serial No. 165,951.

To all whom it may concern:

Be it known that I, LEONARD U. WETHER- ALL, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Sighting Means for Aeroplanes, of which the following is a specification- This invention relates tosighting means for aeroplanes, and more particularly to means for sighting an object upon which it is desired to drop a bomb or other projectile. One of the-main objectsof theinvention is to provide a" sightin means of simple construction and ope'ratlon which may be readily applied to an aeroplane of standard construction. A further object is to pro vide sighting means of the character stated by means of which a sighting telescope may be quickly and easily adjusted at the proper inclination toallow for the speed of the aeroplane, and the velocity of the wind, if

there be any wind blowing. A further object is to provide a device of the-character stated which has luminous means for" ascertaining when the sighting means is perfectly level, thus insuring accuracy of operation. Further objects will appear from the detailed description. 4

In the drawings:-

Figure 1 is a side view of a sighting'apparatus constructed'in accordance with my invention,

Fig. 2 is a back View of part of the same,

15 ig. 3 is .a detail of the objective lens of the sighting telescope,

taken substantiallyon line 5-5 of Fig. 1,

Fig. '6 is a section through the luminous leveling device,

Fig. 7 is a detail,- partly in section, of the means for supporting the telescope, and

Fig. 8 is a side view of antaeroplane with a sighting apparatus constructed in accordance with my invention applied.

-The main supporting frame is provided with the four upwardly and inwardly inclined supporting legs 1, 2, 3, and 4i. i The legs 1 and 2 at the front of thelframe are secured together, at their upper ends, by a hearing block 5 secured thereto- The legs 3 and 4 at the back of the frame are similarly secured together by a bearing block 6. A rectangular telescope-supporting frame 7 is provided at its forward end with a trunnion 8 which is mounted in bearing block 5, a similar trunnion Qbeing provided at the back of the frame mounted in the. bearing 6. By this means, the frame 7 is pivotally mounted on an axis extending longitudinally of the main supporting frame so as' to be .freely rockable transversely of this frame.

An arcuate scale 10 is fixedly secured to the lower section of block 6 and is disposed concentric with' trunnion 9. An indicating needle 11 is secured on the trunnion 9, which is extended for this purpose, and is bent inward to provide an indicator point 12. This point 12 is movable over the upper face or edge of scale 10 which is graduated in both directions from its center, as shown. By this means, the distance to which the frame 7 is tilted in either direction trans versely of the main supportingframe will be accurately indicated on the scale 10, for a purpose to be'desc'ribed.

A telescope supporting block "13 is rockably mounted at the center of frame 7 by means of laterally extending trunnions 14 and 15 which are mounted in the side bars 7 and 7 respectively, of the telesco e-supporting rameq By this means, bloc 13 is pivotally mounted on an axis extending transversely of the frame 7 so as to be freely rockable in either direction longitudinally of the main supporting frame. This block supports a sighting telescope 16 which is secured therein by the diametrically opposite Fig. i is a top plan view of the sighting apparatus, l

Fig. 5 is a fragmentary detail section.

set screws 17 and 18. The telescope I6 is thus supported in a universal mounting so as to be freely rockable both longitudinally and transversely of the ,main supporting frame in either direction. By this construction, the inclination of the sighting telescope may be quickly and easily varied or adjustedto suit circumstances.

A segmental frame 19 is secured to the outer face of side bar 7 b of frame 7, a similar frame 20 bemg'secured to the side bar 7 1 provided at its upper end, with an arcuate scale orbeam 22. This beam is provided needle 30 is secured on rod 29 closely adjacent the inner face of beam 22 and is bent over to form an indicator point-30 which is movable over the scale or series 23 of graduations. A similar needle 31 is secured on rod 28 adjacent beam 24 and is provided with an indicator point 31 movable over the scales 25 and 26. The outer portion of rod 29'is threaded as at 32 and receives a securing nut 33 threaded thereon and provided with an integral operating handle 34. The outer portion of rod 28 is also threaded as at 35 to receive a similar securing mem:

'ber 36. As will be noted more particularly from Fig. 5 of the drawings, the rods 28 and 29 are closely adjacent the under faces of the beams 22 and 24 so that, by turning either one of the securing members 33 or 35 onto its respective rod,the beam adjacent this member will be gripped firmlybetween the same and the indicating finger or needle adjacent the inner face of the beam, thus tightly securing the telescope 16 at the desired incl ination longitudinally of the main supporting frame.

Aset screw 37 is threaded through the upper section of bearing block 6 so as to grip the trunnion 9. By turning the set screw into binding engagement with, the trunnion, the telescope supporting frame 7 may be secured or locked in rocked adjustment laterally of the main supporting frame. By this means, the telescope 16 may be secured at any desired inclination latorally of the main supporting frame, as will beevident.

At the inner side of the main supporting frame, is mounted a spirit level 38. This level is supported by means of the brackets 39 and 40 secured to the legs 1 and 4 of the main supporting frame. A similar level 41 is mounted at the back of the main suporting frame at right angles to. level 38. %y means of these two levels, the observer can quickly ascertain, if the main supporting frame for the sighting apparatus is in a truly horizontal position, 2'. 0., his level both transversely and longitudinally.

In use, this apparatus is mounted on the aeroplane A closelyadjacent and below the observers seat or position indicated by B, with the main supporting frame directed forward and backward of the aeroplane, indicating beam 10 being at the rearward end of the main frame, as shown. When the main supporting frame is perfectly level, the telescope 16 is set at the proper adjustment or inclination depending upon the. speed of the aeroplane, the height, and direction and velocity of the wind, after which the aeroplane is so maneuvered as to bring the object into coincidence with a point 42 on a line 43 marked on the objective lens 44 of the telescope. lVhen the point 42 is on the object, the bomb is released in the usual manner, and if the calculations have been correctly made will strike the object.

In using this sighting apparatus, the direction and velocity of the wind, and the speed of the aeroplane, are ascertained by means of the usual instruments. The apparatus is adjusted to be used with a machine traveling at a given height and speed. Assuming that the apparatus is set for an aeroplane traveling at a. height of 13,000

feet and a speed of miles an hour if there is no wind blowing the scale 25 will be used. In this scale each number represents 10 miles of speed, the spaces between these numbers being marked into 10 equal parts. If there be no wind, and the machine is traveling ahead at 40 miles an hour, the telescope will be secured at such inclination as to bring the indicator p )lIlt 31 above the-numeral 4. With the telescope thus adjusted, the driver of the aeroplane. maneuvers it so as to bring the object into coincidence with point 42 of the objective. lens 44, the observer sighting during this maneuvering through the telescope. As soon as the object is in coincidence, with point 42 the observer releases the bomb which strikes the object which has been sighted at. If there be wind blowing from ahead or against the machine, it will be necessary to incline the telescope more than would be the case where there was no wind blowing against the machine, so as to compensate for the force of this wind tending to drive the bomb backward away from the object. In this case, the scale 23 will be used. If the machine is traveling ahead at .60 miles an hour against a head wind of 30 miles an hour, the indicator point 30 will be set on numeral 3 of scale 23. This will adjust the telescope 16 at considerably less inclination than in the formercase where there was no head wind, so that the bomb will not be released until the aeroplane is much .closer to the object, thus compensating for the tendency of the wind to force the projectile backward away from the object. If the wind is from in back of the machine. the telescope 16 should be set at a much greater rearward inclination to compensate for the tendency of the wind to blow the bomb past or over the-object. In this case, thescale 26 will be used in which, as will be noted from Fig. 4 of the drawings, the

numerals are spaced considerably farther apart than in scale 25. Assuming that there is a wind behind the machine traveling at a velocity of 20 miles an hourthe indicator point 31 will be set at numeral 2 of scale 26, the telescope 16 being thus given a considerable rearward inclination which directs the sighting point 42 of the objective lens 44 forward ofthe machine at such an angle as toallow for the additional velocity imbe tilted so as to be given sufiicient lateral inclination to compensate for this side windage. The scale or beam 10 is so graduated as to permit this lateral adjustment of. the telescope. Assuming that the aeroplane is traveling forward at a speed of 60 miles an hour, with no wind blowing either from in front or in back but a 30 mile wind blowing from. the left hand side of-the machinethe indicator point 31 will be set at number 6 of scale 25, thus giving the proper forwardinclination of the telescope,

after which the telescope supporting frame 7 will be swung toward the left, which wouldbe toward the observers seat, so as to bring the indicator point 12 above number 3 of the scale on beam 10, after which the frame 7 will be secured in adjustment by means of set. screw 27, the telescope 16 having been previously secured in its forwardly inclined position by securing member 33. When thus set, the telescope 16 has both a forward and downward inclination and a lateral inclination, both of which cooperate to insure that, if a bomb is released when the sighting point 42 is brought into coincidence with the object, the bomb will hit this object due to the fact that proper allowance has been made for the speed of the aeroplane and the velocity of the wind. It will be evident that proper adjustments can be quickly and easily made for lateral. head, or rearward winds. 7

To permit this apparatus to be used at night, it is essential that some leveling device for the main supporting frame which is easily visible at night be provided. For this purpose, I provide a hollow glass globe 45. This globe is supported by a concaveconvex plate 46 whichis secured by-a stem 47 to an arm 48 which projects from leg 4 of the main supporting frame. A suitable lining 49 of felt or other suitable material is secured on the inner face of plate 46 and acts as a cushioning means to prevent breakage of globe'45. A rectangular arm 50 is secured to arm 48, the upper arm 51 of which projects above the center of globe 45. A set screw 52 is threaded througharnrtfl, the inner of this set screw being set in a recess at the center of a plug 53 in the globe 45. The globe is further provided with a recess 54,below the plugin which is placed a suitable luminous material, this material being formed preferably from a mixture of alum and sal-soda which has been treated with a minuteamount of radiumto render it lu1ni-' nous, The globe 45 is filled with a suitable liquid so as to leave but a very small air space or bubble in the globe. A cylindrical glass container '55 is then inserted into the globe, after which the globe is hermetically sealed. The container 57 is partially filled with a similar substance to that placed in recess'54. A's globe 45 is rigidly secured to the main supporting frame of the sighting apparatus, and the axis of the globe passing through the screw- 52 and stem 47 of plate 46 .isvertical when the main supporting frame is level, this provides simple and efiicient means for leveling the main frame at night. Vhen the main frame is in such position that the movable luminous element 57 is in such position as to coincide with the fixed luminous elemen-t confined in recess 54, the main frame will be level, as in Fig. 6 of the draw ings. In constructing this luminous level- 1ng device, I prefer to use a relatively heavy liquidin the globe 45, thus avoiding Sudden changes of level bf the liquid such as would result-in splashing or in the possible breakage of the movable luminous element 57.

For-the sake of clea'rness in the description, the direction of travel of the apparatus when applied to an aeroplane is indicated in F igs. 1 and 4 of the drawings by the arrows, and the expressions front and back, and left hand side, have been used with reference to. these two figures, and to Fig. 8 of the drawings. In practice, two or more of these apparatuses may be used, placed in any convenient positions on the aeroplane.

l-Vhat I claim i-s:- I 1. In sighting means, a main supporting -frame, a sighting telescope supported by the frame for free swinging movement longitudinally and laterally of the frame, and means for indicating the extent to which the telescope is swung in either direction.

2. In'sighting means, a main supporting frame, a sighting telescope mounted in said frame for free swinging movement longitudinally and laterally of the same so as to have its inclinationvaried, means for indicating the inclination of the telescope both laterally and longitudinally of the frame, and means for securing the telescope in-adjustment in either direction longitudinally frame, a sighting telescope mounted in said frame for free swinging movement longitudinally and laterally of the same so as to' have its lnclinatlon varied, means for 1nd1- eating the inclination of the telescope both laterally and longitudinally of the frame, and independent means for securing the telescope in adjustment in either direction laterally of the frame.

4.v In sighting means, a main supporting frame, a sighting telescope mounted in said frame for free swinging movement longitudinally and laterally of the same so as to have its inclination varied, means for indicating the inclination of the telescope both laterally and longitudinally of the frame, and meansfor indlcating when the said main supporting frame is in ahorizontal plane.

5; In sighting means,amain supporting frame, a' sighting telescope mounted in said frame for free swin ing movement longitudinally and laterally of the same so as to have its inclination varied, means" for indicating the inclination of the telescope both laterally and longitudinally of the frame, and luminous means for indicating when the said main'supporting frame is in a horizontal plane.

6. 111 sighting means, a main supportin frame, a telescope supporting frame pivot-.

ally mounted in the main frame on an axis extending longitudinally of the same, a telescope supporting block pivotally mounted in the telescope supporting frame on an axis extending transversely of the same, a sighting telescope secured in said block so as to' have its inclination adjusted both longitudinally and laterallyof the main supporting frame in either direction, and means for indicating the inclination of the telescope.

7. In sighting means, a main supporting frame, a telescope supporting frame pivotally mounted in the main frame on an axis extending longitudinally of the same, a telescope supporting block pivotally mounted in the telescope supporting frame on an axis extending transversely of the same, a sighting telescope secured in said block so as to have its inclination adjusted both longitudinally and laterally of the main supporting frame in either direction,'and means for securing the telescope in adjustment.

8. In sighting means, a main supporting frame, a telescope supporting frame pivotally mounted in the main frame on an axis extending longitudinally of the same,

segmental frames secured to each lateral needles carried by the telescope and movable over said graduated beams for indicating the inclination of the telescope in either direction longitudinally of the main frame, and means for indicating the inclination of the telescope laterally of said main frame in either direction.

9. In sighting means, a main supporting frame, a telescope supporting frame pivotally mounted in the main frame on an axis extending longitudinally of the same,

segmental frames secured to each lateral face of said telescope supporting frame and extending upward therefrom, each" of said segmental frames being provided at its upper end with an arcuate graduated beam, a block pivotally mounted in the telescope supporting frame on an axis extending transversely of the main frame, a sighting telescope carried by said block, indicator needles carried by the telescope and movable over said graduated beams, means carried by the telescope and engaging with said graduated beams for securing the telescope in adjustment longitudinally of the main frame, and means for indicating the inclination of the telescope laterally of said'main frame in either direction.

10. In sighting means, a main supporting frame, a bearing block secured at each end thereof, a telescope supporting frame provided at each end with a trunnion fitting into said bearing bloc-ks, one of said trunnions being extended,-segmental adjusting frames secured to .the lateral faces of the telescope supporting frame each provided with a graduated beam at its upper end, a block pivotally mounted in said telescope supporting frame on an axis extendin transversely of the same, a sighting tedescope carried by said block, indicator needles carried by the telescope and movable over said beams, an arcuate indicating beam secured to one of said bearing blocks concentric with the extended trunnion and graduated to indicate the inclination of the telescope in either direction laterally of the frame, and

vided at each end with a trunnion fitting into said bearing blocks, one of said trunnions being extended, segmental frames secured to the lateral faces of the telescope supporting frame each provided with a graduated beam at its upper end, a

block pivotally mounted in sa d telescope supporting frame on an axis extendin transversely of the same, a sighting te escope carried by said block, indicator needles carried by the telescope and movable over said beams, an arcuate'indioating beam secured ment transversely of said main supporting to one of said bearing blocks coneentriewith frame; 10 the extended trunnion and graduated to in- In testimony whereof I aflix my signature dicate the inclination of the telescope in in presence of two Witnesses.

5 either direction laterally of the' frame, means LEONARD U. THERALL.

for securingthe telescope in adjustment lon- Witnesses: gitudinally of the frame, and independent UTMAR R. HUNCKE,

means for securing the telescope in adjust- Cs. STU'BTEVANT. 

